Okay, other then the Joker, Tqo-Face is one of my favorite Batman villains of all time, I've always been intrigued by the way he does things and how he makes up his mind with just a flip of a coin, but this has been bugging me for the past week and I can't figure this one thing out and I'm asking any of you who can answer this question for me to speak out. 
 
I know that when Harvey was hit in the face with acid, his face and psyche was damaged (or "scared") and that he makes all of his chooses with the fild of a coin, but my question is - How does he chose whether he'll commit a crime or do nothing, does he just wake up one day and flip his coin and either go do that crime or does he just go back to sleep? 
 

Its not as simple as Dent simply deciding to be good one day or bad. Harvey is a legal expert and his alter-ego is a homicidal maniac. Obviously Dent can never be a law abiding citizen as his alter-ego won't allow it and both sides are interdependent as a whole. Crime is his only option. Harvey is a legal / criminal mastermind. His alter-ego is a stand alone ruthless killer. His two aspects combined are insane but, effective.
 
The two personas exist at the same time so, when confronted with decisions there are two possibilities: 
 
1) Simple things are automatically decided as their 'no brainers' and both aspects agree on them (the decision to get a sandwhich or get dressed for example)
 
2) If there isn't an agreement on action between the two personalities, Dent flips the coin as a deciding factor of which impulse to act on (Do you black mail someone or, do you shoot them in the face 5 times?)
 
Maybe that helps??